We are developing a technique for estimating the timing of quantal action during neuromuscular transmission. We will use this technique to study the timing of quantal action during facilitation and the effects of the nerve terminal action potential on transmitter release. We are also studying the effects of drugs acting on prostaglandin metabolism on the neuromuscular junction. Inhibitors of prostaglandin synthesis have been found to decrease transmitter release, but it remains to be determined whether this is owing to the effects on prostaglandin synthesis or to other, unrelated actions.